.jpeg "0 For _ In Range(n)")
0 for _ in range(n) in Python
In Python, the syntax 0 for _ in range(n) is a common idiom used to create a list of zeros with a specific length. But what does it actually do, and how does it work?
The _ Variable
In Python, the underscore (_) is a special variable name that is often used as a throwaway variable. It's a convention that indicates the variable is not going to be used anywhere else in the code. In this case, the _ variable is used as a placeholder to ignore the iteration variable in the for loop.
The range(n) Function
The range(n) function generates a sequence of numbers from 0 to n-1. For example, range(5) would generate the sequence 0, 1, 2, 3, 4.
The List Comprehension
The syntax 0 for _ in range(n) is actually a list comprehension, which is a concise way to create a new list from an existing iterable. In this case, the iterable is the sequence generated by range(n). The list comprehension loops over the sequence and creates a new list with n elements, each of which is initialized to 0.
How it Works
Here's a step-by-step breakdown of how 0 for _ in range(n) works:
range(n)generates a sequence of numbers from 0 ton-1.- The
forloop iterates over the sequence, assigning each value to the_variable (which is ignored). - For each iteration, the expression
0is evaluated, creating a new element in the list with a value of 0. - The resulting list is created with
nelements, each initialized to 0.
Example
Let's see an example of how 0 for _ in range(n) works:
n = 5
result = [0 for _ in range(n)]
print(result) # [0, 0, 0, 0, 0]
In this example, n is set to 5, and the list comprehension creates a new list with 5 elements, each initialized to 0.
Conclusion
In conclusion, 0 for _ in range(n) is a concise and efficient way to create a list of zeros with a specific length in Python. By using a list comprehension with a throwaway variable _ and the range(n) function, we can create a new list with n elements, each initialized to 0.
